1. Field of the Invention
The present invention relates to a method of making shape-adaptable and spectral-selective distributed optical radiation source for therapeutic treatment using passive host mediums containing nanocrystals.
2. Description of the Prior Art
The therapeutic effects of light therapy, or phototherapy, have been recognized since ancient times. At present, therapeutic treatment with light and specific color is a widely accepted methodology in various applications. In general, therapeutic light treatment employing low-intensity irradiation is primarily employed in the treatment of skin diseases and physiological problems, such as, carpal tunnel syndrome, tendonitis, rheumatoid arthritis, low back pain, and general pain control. Photo-therapeutic treatment typically affects photoreceptors in the tissue, with consequent alterations in the biochemical processes of the cells. This is accompanied by an increase in local blood circulation and a strengthening of the immune defense system. It has been extensively demonstrated that the use of monochromatic light results in (i) increased flow of oxygen and blood, (ii) decreased inflammation, and (iii) muscle relaxation and pain reduction. Thus, it is widely accepted that absorbed light triggers biological changes within the body, and in such cases, the use of specific wavelengths of light accelerates cellular metabolic processes and stimulates vital chemical reactions. Specifically, light therapy can, for example, (i) increase the circulation by promoting the formation of new capillaries, which accelerate the healing process, (ii) increase DNAIRNA synthesis, which assists damaged cells to be replaced more rapidly, (iii) stimulate collagen protein production, which is important for repairing damaged tissue and replacing old tissue and (vi) shift the cellular redox state which increases pHi toward a more oxidized state when previously it was below optimal for cellular response.
In relation to the foregoing discussion, it is important to note that both visible, especially red, and near-infrared light have been demonstrated to influence many changes at a cellular level. In general, the various tissue and cell types have their own specific light absorption characteristics. In other words, they absorb light at specific wavelengths only. For typically employed wavelength range of 600 to 900 nm, the radiation is absorbed closer to the surface for shorter wavelengths, whereas for longer wavelengths the penetration depth is greater.
It should also be emphasized at this juncture that, as various studies demonstrate, the results of phototherapy are related to the application of light at specific wavelengths and intensities, rather than to coherence effects.
In many cases of light therapy, a careful selection of the spectral content of light used for treatment is of great importance. There were numerous studies confirming the importance of selecting a specific wavelength for light treatment to be optimal. The primary aspect of light therapy is related to cellular regeneration as the result of action of light with the suitable wavelengths and the accurate prescribed doses. Such light therapies typically employ the wavelengths in the range between about 400 and 1500 nanometers, with different wavelengths of light having diverse effects. Whereas the use of lasers (coherent light) has become ubiquitous in various fields in medicine, non-coherent light therapies, employing light-emitting diodes (LEDs) has been proliferating in the past years as well. Typically, wavelengths in the visible range (400-700 nm) and the near-infrared region (700-1000 nm) of the electromagnetic spectrum are employed in light therapies. However, in the context of providing distributed light sources, which are suitable to conform with various body parts during light therapy, lasers and even LED arrays do not provide conformal and adaptable distributed light sources. On the other hand, lasers and LEDs provide high efficiencies. Thus, it would be highly desirable to provide a method of shape-adaptable and spectral-selective distributed optical radiation sources for therapeutic treatment using passive host medium containing nanocrystals that are excited by the said lasers or LEDs. In such a case, the spectral output of the distributed optical radiation source is controlled by the nanocrystal size distribution that determines the spectral output of fluorescence radiation originating from these nanocrystals from within the said host medium, which contains the said nanocrystals, under excitation by an external source. The said host medium, incorporating nanocrystals, can be made of adaptable, geometrically configurable, material that conforms to any desired shape.
Thus, in relation to the foregoing discussion, it is desirable to have a capability of selecting the spectral output and intensity of the optical radiation source according to specific therapeutic requirements. It would also be very advantageous to provide a method of providing an adaptable light-source medium, which can be configured both geometrically and spectrally, and which provides wavelength tunability for therapeutic treatment.